http://www.doitpoms.ac.uk/tlplib/recycling-metals/index.php
While sorting stuff into various bins, the other day, I once again wondered how much energy is saved (and CO2 not made) by, for instance, recycling aluminium cans.
A wet day (????) and Mr Google led me to the link above, to a Teaching and Learning Package from Cambridge Uni. on recycling metals. Though I'm not a materials scientist or a chemical engineer I found enough of it understandable. I just skipped the Hard Sums and the chemistry that was beyond my 1960s O Level. I'm looking forward to reading the one on recycling plastics, next.
It seems that new aluminium made by processing Bauxite, the ore, requires some 260 units of energy per kilo of metal produced, while to produce a kilo of aluminium from recycled sources takes only 6 to 10 units.
It's not quite that simple, but it makes you think, doesn't it?

A funny addendum. A friend of mine relayed a story that had been told to him by a friend of his who had been on holiday to India, I think. The location doesn't matter. This man was drinking a few cans of beer outside a roadside café and there was a teenage boy going around collecting the tins for whatever meagre earnings he could get for them and putting them into one of those sand/ballast/gravel bags we have here in the builders merchants. This man then crushed the can underfoot and threw it into the bag, the boys face lit up at this amazing revolution and tipped the contents of his bag out on the ground and a frenzy of crushing cans ensued. Now he had realised that he could collect many many more times the amount in the same bag before bringing them to the point of sale._________________“It’s my field. It’s my child. I nursed it. I nourished it. I saw to its every want. I dug the rocks out of it with my bare hands and I made a living thing of it!”

The economics and sustainability for most packaging products stacks up similarly- the real challenge is for composite materials such as tetrapaks or (my own least favourite way of serving something that may have once been a potato- the Pringles tube). Once you have to start separating a packaging item into it's component parts it adds to the cost and reduces the viability of recycling. So the plastic milk bottle is a much better option than the tetrapak for example.
One of the great missed opportunities in building sustainability into the area was in not forcing manufacturers to use certain types of plastic above others- so PVC (the "five" triangle symbol) is really difficult to recycle whereas PET ("one) and the PE ("two" and "four") are much easier. Unfortunately, the "morkeshing goys" (think Ross O'Carroll Kelly) prefer packaging to look a certain way so we are stuck with a very imperfect system.

I agree completely. So much packaging consists of a film of one material laminated to another and this adds considerably to the difficulty and cost.

There is one kind of pressure that the marketing people do respond to, though, and that is consumer pressure. One effective way of persuading them to change practices is not to buy over-packaged goods. Another is to support the various Environmental NGOs, who can exert the clout to influence legislation. Think how little foamed polystyrene (hard to recycle) is used as packaging nowadays - papier-mâché from recycled paper has largely replaced it. I'm sure some of that is down to cost-saving, but consumers are increasingly well informed and are making choices.

I suppose the hardest choice to make though, is not to buy in the first place. I'm reminded of those posters one sees in TV programmes set during WW2 : "Is Your Journey Really Neccessary?" It is rampant consumerism, driven by the mechanisms of capitalism, that has got us into this mess!
Perhaps nowadays we should be asking "Is Your Purchase Really Neccessary?"

i know it's not a popular opinion, but i'm cautiously supportive of the idea of municipal incinerators.several examples above mention plastics or composites which are difficult to recycle; so i've no major issue with burning these 'frozen' oils to generate electricity; it's my understanding that a gas boosted incinerator burns hot enough that there's no major concern about pollution - bar CO2 obviously - but sure we'd be burning coal to produce the electricity otherwise.

I suspect you have opened up a can of worms there, MK! But I'm inclined to agree with you. Quite a lot of our plastics products are difficult or impossible to recycle. Recovering their energy content makes sense as long as it doesn't generate dioxins and other nasties. However, more thoughtful materials selection together with changes in practices of sales and distribution might avoid the need for these materials in the first place. Bread doesn't need to be packed in polythene bags or on plastic trays. We often don't really need co-extruded films for packaging, though the marketeers like them. Etc.

maybe you'd have a situation where if plastic could be used (safely) as a fuel, people might think twice about littering. it could end up with a value, it'd be like throwing little bits of firewood away...

Now that you mention burnable stuff that gets thrown away, what about all the take-away boxes that get dumped in the ditches around here? With a bit of tweaking it could probably be converted into firelighters. An idea for a new business? Only joking!

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